Heretofore, ultraviolet radiation intensity-measuring apparatus wherein a selenium photoelectric cell is used as a detector and a color filter glass transmitting ultraviolet radiation is combined thereto, and the like have been commercially available as ultraviolet radiation-measuring apparatuses. However, these measurement apparatuses have the disadvantage that it is only possible by these apparatuses to measure intensity of ultraviolet radiation at the point of time when measurement is carried out and it is impossible to measure total quantity of ultraviolet radiation received in a certain period of time as an integrated value.
Further, although ultraviolet radiation-measuring apparatuses wherein an integrator and a recorder are connected to such a measurement apparatus to make it possible to measure integrated value of quantity of ultraviolet radiation are commercially available, these apparatuses have disadvantages, for example, that they are very expensive and hard to easily carry, and thus they are used only in small numbers for research, etc.
Further, various simplified integrating pyrheliometers, for example, pyrheliometers wherein a chemical method such as a diazo photosensitive paper method, uranyl oxalate method, astra-benzene method or chlorophyl method is used have recently been made on an experimental basis and proposed for use in cultivation control of farm products. However, these pyrheliometers chiefly aim at measurement of amount of received beam in respect of visible radiation part useful for farm products, and thus it is impossible to specifically measure amount of received light in respect of beam in the ultraviolet region. Moreover, substances such as diazo compounds, uranyl oxalate and chlorophyl used in the above pyrheliometers have inconveniences, for example, that they must be prepared at the time of use because they coagulate at high temperature or at low temperature or have bad preservability, and further these substances have disadvantages of low accuracy, poor reproducibility, being poisonous and the like.
Thus, the present invention has been developed in order to obviate the above disadvantages which usual techniques have, and aim at provision of simple and highly accurate measurement apparatus and method which make it possible to measure integrated amount of received light in respect of ultraviolet radiation in the particular wavelength region.